What energy-efficient features should your replacement windows have? According to the Efficient Windows Collaborative (http://www.efficientwindows.org), a group of insulation and window manufacturers that comply with federal energy requirements, new windows should have low-e coatings, which let in visible light but block radiant heat losses to cut heating bills.
The nonprofit Alliance to Save Energy (http://www.ase.org) in Washington, D.C., maintains that replacing windows adds value to a house in several ways. It improves the appearance and resale value of the home. It reduces maintenance costs such as painting and makes cleaning easier with tilt-sash designs.
In new construction, standard windows are not that expensive compared with the total cost of the house. Special windows—transoms, half-moons, and Palladian—add a considerable amount to the cost, however. Windows in new houses, in fact, can approach 3 percent of the sale price. For a $300,000, 3,200-square-foot house, that means $9,000.